A nanopowder combustion reaction method is a method of synthesizing nanopowders by using a precursor in a gaseous state, liquid state or solid state. Generally, a special combustion reactor (burner) is needed for combustion reaction of a fuel in a gaseous state. The combustion reactor is classified into a diffusion type combustion reactor and a pre-mix type combustion reactor according to a gas supply method.
The diffusion type combustion reactor is a most common form of a combustion reactor, which is generally configured by arranging three cylindrical nozzles for supplying a precursor gas, a fuel gas and an oxidized gas, respectively, in a concentric circle form. The thus-constructed diffusion type combustion reactor is advantageous in that the structure is simple, but has a problem in that it is difficult to induce uniform reaction in the combustion reactor as reaction is made only on a contact surface of each gas because different kinds of gases are supplied via the respective nozzles.
Besides, as oxide grows in the combustion reactor, the oxide is deposited on the nozzle surfaces, which makes it difficult to sustain a continuous and uniform reaction.
The pre-mix type combustion reactor is to pre-mix each of gases in a pre-mixing chamber and then reacting them in a combustion chamber, which was proposed in U.S. Pat. No. 4,589,260 (Title: Premixing Burner with Integrated Diffusion Burner, field: Nov. 4, 1983). Such a pre-mix type combustion reactor is able to solve the aforementioned problem of the diffusion type combustion reactor, however, is problematic in that a precursor gas and fuel gas introduced are easily oxidized or combusted in a mixing process.
Moreover, the form of produced nanopowders depends sensitively on which region of the combustion chamber a reaction occurs at, thus it is hard to precisely control.